In certain laboratory tests, it is necessary to maintain specimens at a stable low temperature for a considerable length of time. The present practice is to place a few drops of the specimen in a test tube and place the test tube in crushed ice. Frequently, a number of test tubes are placed in the same crushed ice container which results in water from the melted ice adhering to the bottoms of the test tubes. Thereafter, when a test tube is removed for further processing, the drops of water about it may fall downwardly into the remaining test tubes, thereby introducing foreign material into those test tubes remaining.
Further, there is always a question of whether all of the test tubes are subjected to uniform temperature conditions -- this being significant to provide reproducibility of results, as in an assay or the like. This is particularly important in binding interactions where the affinity constant increases as the temperature decreases, i.e., approaches 0.degree.C.
Through the practice of the invention, the objectionable drawbacks of the prior art are avoided and a number of advantages provided. More particularly, in the practice of the invention, the test tubes are mounted in a unique fashion in a holder which includes a base portion and a superstructure portion integral therewith. The base portion includes a sealed container substantially filled with a freezable liquid and has a top surface equipped with recesses to receive the bottom portions of test tubes. The superstructure has a plurality of apertures therein aligned with the aforementioned recesses for supporting and stabilizing the test tubes a spaced distance above the base portion.
Other advantages of the invention may be seen in the details of operation and construction set down in the ensuing specification.